Slash Claw and abilities like it will be based off of the Recklessness before Recklessness reduction. So... if you have Blazvatan, and cast Enre-hep's ability on him to give him 30 Recklessness, then Slash claw would deal 65 damage.

There are some pretty cool combos like Carnivores Keening and such, but Warbeasts are a bit weak in masters.